The present invention relates to the lubrication of railroad tracks and, in particular, to an improved method of controlling the amount of lubricant applied to the tracks of a switch yard.
It is well known that the application of a lubricant to the surfaces of railroad tracks improve the rollability of railroad cars thereby significantly reducing the rate at which the tracks become worn by the wheels of the cars which move along them. Lubricating the tracks also reduces the wear to the wheels of the cars. Curves and switches are particularly subject to wear.
The cars of a train are disassembled and reassembled into new trains in a yard which has numerous parallel tracks that are accessible from the opposing ends thereof by access tracks connected by switches. The track, including curves and switches, are currently lubricated by injecting a lubricant through outlets on to the surface of the tracks.
Within the yard the cars of an incoming train are disassembled and recombined with cars from other incoming trains into a plurality of new outgoing trains, with the cars of each new train lined up on a separate track in the yard. One method is a hump yard for such purposes, where a switch engine moves a car over a hump at a speed of approximately three miles per hour. The cars are independently released on the crest of the hump and allowed to roll down the far side of the hump and across switches to tracks on which the new trains are being formed.
In a hump yard, the speed of the car as it moves along the track system is controlled by a series of retarders. A computer associated with each retarder receives information regarding the weight of the incoming car and has a sensor for determining the speed at which the car is entering the retarder. It also maintains as count of the number of cars being directed to each yard track and adjusts the application of the retarder based on the incoming speed, the weight of the approaching car and the space remaining on the yard track. Other sensors in the system follow the car""s progress across the switches of this system and prohibit the premature throwing a switch along the path of a rolling railroad car. Except for weight, the retarders of a hump yard system are not responsive to the condition of an individual car or to the condition of the track.
The dispensers now being used to lubricate the tracks of a yard system have an associated detector for detecting that a car is approaching and the dispenser dispenses a fixed amount of lubricant each time a car passes. When the tracks are properly lubricated, a railroad car that does not have its brake applied and is free of defects will move along the tracks of the system at a predictable rate. In reality, however, several factors affect the amount of lubricant needed to maintain the optimum rollability of cars aver the tracks. Over lubrication will cause excess lubricant to build up in the yard tracks. Excess lubricant is a hazard to railroad personnel, can cause roll out, can cause damage to the cars and the contents thereof, and contaminates the underlying ground.
Water is a natural lubricant and, therefore, a lesser amount of lubricate is needed on the tracks during rain or snow. On the other hand, rain or snow will wash some of the lubricant off the tracks leaving the tracks in need of restoration of the desired level of lubrication after the rain has ended. Cars moving along the tracks of an adequately lubricated yard system will lose speed at a predictable rate thereby allowing the orderly assembly of the cars on the yard tracks. On the other hand, the cars move more slowly along inadequately lubricated tracks, as occurs following a rain storm.
Lubricant which is dispensed on a track is picked up by the wheels of a moving railroad car and spread down track. Once a few cars have applied lubricant to a previously underlubricated track, the cars will again begin moving at their desired speeds, after which only intermittent application of lubricant are needed to maintain adequate lubrication. It is unnecessary, therefor to apply lubricant to the tracks each time a car is released over a hump as currently done in a hump yard.
All of the foregoing problems could be reduced or eliminated by providing a means of measuring the need for lubricant on the tracks of a yard system and controlling the application of lubricant in response to the measured need. Until the present invention, the railroad industry has not had such a means for measuring the need for lubricant on the tracks of a yard system.
Briefly, the present invention is embodied in a method of controlling the application of lubricant to the tracks of yard rail systems of the type having an access track leading to a plurality of switches and then into a second plurality of yard tracks into which moving railway cars can be directed. In accordance with the invention, a primary lubricating station is provided immediately following the primary retarders. Where the yard has a hump, the primary retarder is positioned immediately after the hump. A speed detector detects the presence and the speed of a railroad car approaching the primary lubricating station. Secondary lubricating stations may be provided down track to lubricate the yard tracks as needed. Each lubricating station has a reservoir of lubricant, a positive displacement pump, and a plurality of nozzles arranged to apply lubricant along a portion of rail having a length approximately equal to the circumference of a wheel of a railroad car. Positioned down track, along each of the yard tracks of the system, are detectors for detecting when a rail car has passed.
A logic, which may be a computer, receives input from the speed detector and the down track detectors and calculates the speed of the car as it moves through the tracks by dividing the length of track between the primary lubricating station and the down track detector by the time needed to pass between the two points. The calculated average speed of the car is then compared to a predetermined desired speed retained in the memory of the computer. The difference between the desired speed and the actual car speed is used by the logic to control the rate at which lubricant is applied to the tracks. When the logic determines that cars are losing speed more rapidly than desired, the logic will cause the pump and the nozzles to dispense lubricant immediately before the next railroad car reaches the station. On the other hand, were the logic to determine that the speed of cars down track equals the desired speed, the amount of lubricant being dispensed on the tracks will be reduced or terminated.
Occasionally a car will move along the tracks of a system at an excessively high rate of speed or at an exceptionally low rate of speed. A car will move at an excessively high rate if the retarder does not function properly or has failed altogether. A car will move at an exceptionally slow rate of speed if the brake on the car is being applied or if the car is defective in some manor. In accordance with the invention excessive speeds or exceptionally low speeds are detected by a speed detector located before the primary lubrication station. When the logic determines that the initial speed of the car does not fall within expected perameters the system will not apply lubricant to the tracks ahead of the car and the speed of the car will be ignored for determining the need for further lubrication of the tracks. Also, the system will identify an exceptionally slow moving car so that the car can be checked before it leaves the yard. It is far more expensive to deal with a defective car on the open track than in a yard where repairs can easily be made.